Is there any documentation or research done on this field.
From a quick search, it is:
Or I make multiple withdrawals from the casino to different addresses, send them around a bit in my own wallets, consolidate the UTXOs, and finally move them to Coinbase.
You won't obviously get an answer to this from Coinbase, for if you did, you could avoid their method and convert your "tainted" coins to "clean" in an different way. It's basically whatever they want. I'm sure that once you deposit your coins, they'll start sharing your chain's info with the lords of "chain scouting"; chainalysis, elliptic, etc.